44 ROYAL SOCIETY OF CANADA 



The numerous medullary rays are chiefly one cell wide, but occa- 

 sionally one of greater width is to be seen, and it then shows numerous 

 large, thyloses in its central portion. 



Radial. — In the radial section the details of structure are not as well defined 

 in consequence of the extent to which alterations had been developed 

 through decay. It was, therefore, not possible to make as clear a 

 specific diagnosis as would have been desirable, in order to establish 

 exact relations with other species, but enough were recognizable to 

 justify certain conclusions. Under a moderately low power the 

 medullary rays may be seen to be composed of elements of one kind 

 only, i.e., parenchyma cells, while the walls appear to be thin and 

 not pitted. Nevertheless, under a higher power it may be seen that 

 decay had operated to such an extent as to obliterate all structural 

 markings. Resin cells are frequent in the wood and at once to be 

 recognized by their abundant, dark coloured and granular, resinous 

 contents. The individual cells are several times longer than broad, 

 and terminated by transverse walls. They present no structural 

 peculiarities which might serve to differentiate this wood from that 

 of other Sequoias. 



The tracheids occasionally present sufficiently well preserved 

 structure to permit a recognition of the bordered pits which are chiefly 

 in two rows and large as in S. sempervirens. In this respect it differs 

 from S. langsdorfii where the pits are more generally in one row, and 

 the affinity thus appears to be in the direction of S. gigantea. 



One of the most remarkable structural features is exhibited in 

 the presence of numerous thyloses in certain of the medullary rays, 

 due to the development there of resin canals. This feature will be more 

 appropriately discussed in connection with the tangential section. 



Tangential. — The resin cells are seen to have the same aspect as in the radial 

 section, being about 2 — 3 times longer than broad, and as in the 

 latter, a very thorough search has abundantly proved that there are 

 no resin canals penetrating the structure in a longitudinal direction. 

 The relative positions of the transverse and longitudinal sections 

 was such that structures belonging to the one must have been shown 

 in the other if present, and I therefore feel no hesitation in the 

 statement that resin canals traversing the wood longitudinally, do 

 not constitute a structural element of this species. The full signifi- 

 cance of this fact does not appear until the longitudinal, and especially 

 the tangential sections are brought under examination. Tangen- 

 tially the medullary rays are seen to be of two kinds, a fact noted by 

 Sir William Dawson in 1875.^ In the first case the most numerous 

 rays are of the ordinary, uniseriate type, and present nothing which 

 will serve to disinguish them from the simple rays of other species 

 of Sequoia. In the second case one may notice a number of rays of 



' B. N. A. Bound. Comm., App. A, 331. 



